JApplets have contentPanes which I believe are usually JPanels (though they could be set to be any object derived from Container). So one way to derive a JPanel from a JApplet is to call getContentPane() on the JApplet object. Having said this, I'm not recommending that you do this, but rather you probably should re-write the app to create a JPanel from the beginning. Then if you want to place this JPanel in a JApplet or JFrame (or JDialog), you do so easily by calling getContentPane().add(myJPanel).